Pressure vessel locking ring



FIG. 1 is a front view of a pressure vessel locking ring showing the new design;

FIG. 2 is a left side elevation view thereof;

FIG. 3 is a right side elevation view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a rear elevational view thereof with the dotted line indicating that the end of the ring forms no part of the design; and,

FIG. 7 is a perspective view of the locking ring of FIG. 1 shown in expanded condition to emphasize its helical shape. 

We claim the ornamental design for a pressure vessel locking ring, as shown and described. 